How the next big animated hit 'Sing' was made over 5 years

• The movie "Sing" took a long time to make.• Part of that was because they needed to get the rights to the songs.• They also had to nail down the personality of the lead character.

Director Garth Jennings already has a very energetic personality, but having spent five years developing and making the animated movie "Sing," he admits he's now just a big ball of nerves leading up to its December 21 release.

"It's been very emotional, actually, and I don't use that word lightly," Jennings recently told Business Insider about showing the movie to preview audiences for the last month.

Known for his music video work in the 1990s, he took on directing the adaptation of a book regarded in the industry as an unmakeable movie, "The Hitchhiker's Guide to the Galaxy" in 2005, which ended up being a critical dud (though it earned over $100 million at the global box office). Jennings rebounded with the inventive indie "Son of Rambow" in 2007, about two boys obsessed with the first Rambo movie. Since then, he's been trying to develop an animated movie.

Garth Jennings. Frederick M. Brown/Getty But having never made an animated movie, Jennings was a little naive on how it's done.

So five years ago Jennings had a meeting with producer Chris Meledandri, the man behind the "Despicable Me" movies and this year's animated hit "The Secret Life of Pets," and by the time it ended Jennings agreed to make Meledandri's next movie.

"Chris just started talking about his thoughts and they just smashed together with my sensibility and my hopes and dreams for making an animated film," Jennings said.

The idea Meledandri had was for a movie about a shifty theater owner whose only way to save his business is to put on a singing competition to give notice to an unknown talent. And seeing as this was an animated kids' movie, it would be filled with pop songs and all the characters would be animals.

"There would be a hook of it being a singing competition but then it is a portal into what becomes a character movie," Jennings said. "I didn't take any convincing at all, it wasn't like 'oh, I don't know,' I just jumped in."

And that began a five-year process to bring "Sing" to the screen.

For Jennings it was a learning experience from the start. After writing a traditional story treatment and first draft of the script, the story was suddenly cut up and dissected by Meledandri's team at Illumination Entertainment into a storyboard version of the movie, and that's when the real work started.

"You start to rewrite and find out what works," Jennings said. "If a gag is too late, you're rewriting throughout, which you don't do on a live-action movie."

The cast of "Sing" with their characters. Universal One of the biggest changes was the theater owner, Buster Moon. Voiced by Matthew McConaughey, the fury koala bear is barley keeping his theater afloat as he often is on the run from the bank looking for money he owes it. Thinking back on the early drafts of how Moon operates, Jennings felt he came off a little as a scam artist.

"He did start off on paper being a little more of a charlatan," he said. "There's a fine line dealing with a character like that where they are kind of con people a bit. Chris and I found early on that he became a bit too unlikable because we were pushing that button too much. He was being a little too rude. And his likability went down for us. This was before we even showed it to audiences."

Though changes to the characters and story were constant, Jennings admits it wasn't stressful because often he was only dealing with Meledandri.

"I only had notes and discussions from one person and that was Chris," he said. "No director even on a live-action film has so few voices. Now my editor and production designer and the animation team have an opinion and everyone has an idea of what they are doing, but the core creative storytelling aspect of it involved discussions between myself and Chris."

Another big aspect of "Sing" is the music featured: 85 songs, ranging from classics by Frank Sinatra to current pop singles played throughout either over scenes or sung by the competition contestants, who are voiced by the likes of Reese Witherspoon, Scarlett Johansson, Seth MacFarlane, Taron Egerton, and Tori Kelly.

Jennings even wrote specific songs into the script, like the Rosita character (Witherspoon) singing Katy Perry's "Firework" when she's introduced in the movie or Elton John's "I'm Still Standing" played by Johnny (Egerton) as his big number in the end.

"Sing." Universal The latter moment involved a six-month process to get the okay from John, including Jennings sitting down to close the deal.

"And it wasn't because Elton's company was being tricky," he said. "They were thinking that they were going to be using it for something they were working on. So I went and had a meeting, I showed them the scene of Johnny playing the song, and they completely understood why we wanted to use it and they loved the way we used it. But before that it was six months of not getting it."

For Jennings, the most fun was working with the talent in the recording booth. Each actor was different, he said. McConaughey came in full of energy and just wanted to jump in the booth and go. While someone like Witherspoon took her time and wanted to figure out everything going on before recording. And then there was Tori Kelly, who is known more for her singing than acting. Her character Meena, a shy elephant who has an incredible voice, is very much the emotional center of the movie, so Kelly's performance had to have a lot of layers to it.

"She had never done that kind of performance before and very often she was playing her character opposite Buster who is a ball of energy," Jennings said. "So I would be in the booth with her, jumping around being the character she was playing against, and they would have to cut me out of the soundtrack so you only hear Tori."

Though Jennings is still nervous about how general audiences will react to the movie, he feels good about the preview screenings. And the movie recently received Golden Globes nominations for best animated movie and best original song.

In the future, he still wants to make live-action work, but he admits he also wants to do another animated movie.